Hmmm... I'm wondering if the figures for NEF and NEF+JPEG Basic are correct. Seems to me the amount for a 128MB-card.
As for the cards: I was planning to buy 2 512MB's but now I'm more up to 2 256MB's with an Imagetank as an addition. The amount you save on the difference between the price for 2 256MB's and 2 512MB's can be used for the Imagetank with some €'s or $'s or whatever added.